Biodegradable moisture absorbing composite and methods for producing same

Abstract

The present application discloses biocomposites containing a polymeric matrix comprising at least one biopolymer having an amino (-NH2) or hydroxyl (-OH) side group, and from 30 to 85% (w / w) of a bark flour with a particle size from 500 to 1500 mesh. Products comprising the biocomposites and methods for producing thereof are also disclosed.

Description

BIODEGRADABLE MOISTURE ABSORBING COMPOSITE AND METHODS FORPRODUCING THE S AMEFIELD OF THE INVENTION

[0001] The present disclosure is directed to biodegradable compositions and their use, for example, packages.BACKGROUND OF THE INVENTION[0021 Packaging plays a crucial role in the food production process and supply chain, continuously working to ensure food safety and quality. Its primary purpose is to maintain food quality and safety while minimizing food waste and the incidence of foodborne illness. However, it is crucial to achieve meeting all quality standards while at the same time providing cost-effectiveness and efficiency.

[0003] Food packaging systems must prioritize protection against environmental contaminants, foreign odors, dust, physical damage, and mechanical impact. They must also effectively shield against temperature changes, moisture, gases, light, microorganisms, and other factors throughout the product's life cycle.

[0004] Modem packaging materials are actively being developed to extend the shelf life of food products both before sale and after purchase. To prevent oxidation, pathogen penetration, and to improve overall preservation, so-called "active packaging" materials are used. These materials adapt to the environmental conditions but at the same time offer tailored protection throughout transportation.

[0005] While adaptive moisture-absorbing packaging systems offer significant benefits, such as reduced food waste and increased shelf life, they also present sustainability challenges. Most conventional packaging systems rely on mineral -based plastics, which are non-renewable resources and contribute to greenhouse gas emissions during production and disposal. Polymeric moisture absorption materials are also inherently composite, often consisting of multiple components separated by phase boundaries or multilayered structures.

[0006] The importance of moisture control extends beyond food packaging. Products ranging from electronic components to sensitive equipment also require moisture-free environments for optimal functioning. While these items are typically packaged in nearly impermeable containers, moisture can still seep through over time or become trapped initially. In such cases, it becomes crucial to implement a desiccating method within the packaging to absorb moisture without affecting other components.

[0007] Unfortunately, packages designed for moisture control usually combine different materials and complex structures and are often composed of multiple parts. This intricate design increases manufacturing costs and complicates recycling or composting processes.

[0008] Accordingly, there is a need to develop cost-effective, secure, and sustainable packaging.

[0009] EP0400460B1 discloses a formulation of a material made of thermoplastic resin and magnesium sulfate, mixed in a certain percentage. In addition, calcium chloride, aluminum oxide, silicon oxide, cobalt oxide, barium oxide, and zeolite are disclosed as other substitutes for magnesium sulfate.

[0010] US 5432214 discloses polymer-based dehydrating materials, including one or more thermoplastic or thermosetting polymers, one or more dehydration agents, one or more elastomers, and fibers of a specific length, such as synthetic, vegetable, and animal fibers, in predetermined proportions. A molecular sieve or silica gel can be used as the dehydration agent.[Oil ] EP2093162A1 describes a material that is a moisture-absorbing polymeric product composed of a mixture of a non-elastomeric polymeric material and a water-absorbing agent with at least two components, at least one of which swel ls when exposed to water.

[0012] These solutions are mostly based on synthetic thermoplastic polymers to which certain inorganic substances are added, to improve the absorption properties of the material.SUMMARY OF THE INVENTION

[0013] In one aspect of the disclosure, a biocomposite comprises a polymeric matrix comprising at least one biopolymer comprising an amino (-NHz) or hydroxyl (-OH) side group, and from 30 to 85% (w / w) of a bark flour with a particle size from 500 to 1500 mesh.

[0014] Preferrably, a biocomposite comprises a polymeric matrix comprising at least one biopolymer comprising an amino (-NH?) or hydroxyl (-OH) side group, and from 30 to 60% (w / w) of a bark flour with a particle size from 500 to 1500 mesh.

[0015] In some embodiments, the biopolymer and the bark flour are crosslinked.

[0016] In some embodiments, the biopolymer comprises a protein-based biopolymer, a polysaccharide, peptidoglycan, polyhydroxyalkanoates (PHAs), or any combination thereof.

[0017] In some embodiments, the bark flour comprises tree bark, preferably bark of oak, poplar, elm, pine, black locust, acacia, eucalyptus, beech, hornbeam, chestnut or any combination thereof.

[0018] In some embodiments, the bark flour comprises coffee granules in a ratio from 1 :0.01 to 1:0.2 (w / w) respectively.

[0019] In some embodiments, the bark flour comprises cacao pulp in a ratio from 1:0.05 to 1:0.1 (w / w) respectively.

[0020] In some embodiments, the bark flour comprises a modified surface treated with a compatibilizing agent comprising water, glycerin, a polyol, preferably a bio-polyol, urea, polycarboxylic acid, preferably plant-based polycarboxylic acid, or any combination thereof.

[0021] In some embodiments, the biocomposite comprises a coating layer surrounding at least a portion of a surface of the biocomposite, wherein the coating layer comprises a bio-polymer or a natural wax.

[0022] In some embodiments, the biocomposite is in the form of a sheet or a pellet.

[0023] In some embodiments, the biocomposite further comprises a natural additive selected from the group consisting of: a coloring agent, a filler, a release agent, a binder, and any combination thereof.

[0024] The biocomposite according to the present invention is biodegradable and moistureabsorbing.

[0025] The product according to the present invention comprises the biocomposite, wherein the product is a bottle, a container, a package, a cap, a disposable medical equipment, a construction material or any combination thereof.

[0026] A method for producing a biocomposite according to the present disclosure, includes: 1) contacting a biopolymer comprising an ammo (-NH2) or hydroxyl (-OH) side group, with 30 to 85% (w / w) of a bark flour with a particle size from 500 to 1500 mesh, preferably at a temperaturefrom 100 to 200 °C, more preferably at a temperature from 120 to 160°C, ii) forming a homogeneous biocomposite.

[0027] In some embodiments, the contacting comprises mixing the biopolymer and the bark flour under mechanical mixing.

[0028] In some embodiments, the bark flour is gradually added to the biopolymer.

[0029] In some embodiments, the method further comprises a step iii) shaping the biocomposite into pellets or sheets.

[0030] In some embodiments, the method further comprises a step iv) applying a coating layer comprising a bio-polymer or a natural wax to the biocomposite, wherein applying is by coextrusion, pressing, casting, spraying, or any combination thereof.

[0031] In some embodiments, the method further comprises a step preceding step i) of treating the bark flour with a compatibilizing agent comprising water, glycerin, a polyol, preferably a biopolyol, urea, polycarboxylic acid, preferably plant-based polycarboxylic acid, or any combination thereof, at a temperature between 70°C and 100°C, preferably the step is performed in a highspeed mixer, more preferably from 1000 to 3000 rpm.

[0032] In some embodiments, the compatibilizing agent comprises citric acid, urea, water, glycerin, or any combination thereof, preferably from 5 to 25 g of citric acid or urea, from 150 to 300 ml of water, and optionally from 0.1 to 20 g of glycerin.

[0033] In another aspect of the disclosure, a method for producing the product according to the present disclosure, includes: a) providing a template comprising a wall defining a cavity, wherein the shape of the product is at least partial ly predetermined by a shape of the wall; b) contacting the template with the biocomposite according to any one of claims 1 to 12, to at least partially fill the cavity, wherein the contacting is carried out by casting, injection molding, extrusion, compression, thermoforming and / or any combination thereof, thereby obtaining the product.

[0034] In some embodiments, the method further comprises a step of releasing the product from the template, wherein releasing is preferably after waiting a period of time. The waiting time will depend on the type of compatibilizing agent. It is expected to range from 3 to 60 seconds.

[0035] In some embodiments, the method further comprises a step of introducing a moisture sensor, temperature sensor, or both to the obtained product.

[0036] The biocomposite according to the present disclosure provides control of the humidity in a closed space.

[0037] In addition, the biocomposite according to the present disclosure may be used in construction materials, electronic devices, food, cosmetics, medicine, chemical-, or electronic-product packaging, or any combination thereof.

[0038] The product according to the present disclosure provides control of the humidity in a closed space.

[0039] In another aspect of the disclosure, a use of the product according to the present disclosure, is in construction materials, electronic devices, food, cosmetic, medicine, chemical-, or electronic- product packaging, or any combination thereof.

[0040] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary’ skill in the art to which the disclosure pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the disclosure, exemplary methods and / or materials are described below. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

[0041] Further embodiments and the full scope of applicability of the present disclosure will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this detailed description.BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 illustrates a product according to the present invention.DETAILED DESCRIPTION OF THE INVENTION

[0043] According to the present disclosure, a biocomposite is a moisture-absorbing biocomposite comprising a polymeric matrix comprising at least one biopolymer comprising an amino (-Nil?.) or hydroxyl (-OH) side group, and a bark flour.

[0044] The present disclosure is based, in part, in biodegradable composites, comprising biopolymers and natural fillers, offering sustainable alternatives to known petroleum-based plastics. .According to the present disclosure, bark flour is used as the filler within a biopolymer matrix.

[0045] .According to the present disclosure different tree species' shredded bark (bark flour) absorbs a specific volume of moisture from a confined environment.

[0046] According to the present disclosure biocomposites comprise solely materials from renewable resources, and decompose under controlled conditions.

[0047] In addition, biocomposites as described herein regulate humidity within a confided space, thereby extending e.g. a product shelf life.

[0048] The term "bark flour" as used herein refers to flour made from the dried and ground bark of a tree, or a plant, such as shrubs and vines. Non-limiting examples of trees include oak, poplar, elm, pine, black locust, acacia, eucalyptus, beech, hornbeam, and chestnut, and combinations thereof.

[0049] According to some embodiments of the present disclosure, a biocomposite comprises: a polymeric matrix comprising at least one biopolymer comprising an amino (-NH2) or hydroxyl (- OH) side group, and from 30 to 85% (w / w) of a bark flour with a particle size from 500 to 1500 mesh.

[0050] In some embodiments, the biopolymer and the bark flour are crosslinked.

[0051] According to the present disclosure, a biopolymer comprising an -NH?. or -OH side group, allows for the crosslinking reaction between the polymer matrix and bark flour (filler). In some embodiments, crosslinking is through a crosslinking agent such as polycarboxylic acid or citric acid.

[0052] According to the present disclosure, a biopolymer as disclosed herein is for injection molding. The present disclosure is based, in part, on the finding that the particle size of the bark flour influences the ability to use the biocomposite in injection molding.

[0053] However, comparable composite materials comprising bark flour with a particle size of more than 1500 mesh are not suitable for injection molding.

[0054] Moreover, bark flour with a particle size of less than 500 mesh will lead to increased force and / or energy applied to a mixing process of the flour and biopolymer, to achieve appropriate blending and / or dispersion of bark flour and biopolymer.

[0055] In some embodiments, the biopolymer comprises a protein-based biopolymer, a polysaccharide, peptidoglycan, polyhydroxyalkanoates (PHAs), or any combination thereof.

[0056] .As used herein the term “biopolymer” refers to a molecule comprising repeating units, called monomers, which are derived from a biological source such as plants, animals, or microorganisms. These polymers are naturally occurring or produced through biological processes. A biopolymer often contains functional groups, such as NH2 (amine) or OH (hydroxyl) groups. The term "side group" refers to additional chemical groups attached to the main polymer chain. These side groups can significantly influence the properties and behavior of the polymer.

[0057] A suitable biopolymer according to the present invention is any biopolymer with reactive - NH2 or -OH side groups in the mam chain. Non-limiting examples of suitable biopolymers according to the present disclosure include chitin, cellulose, starch, thermoplastic starch (TPS), starch-based polymers, collagen, collagen-derived polymers, keratin, polyesters, polyhydroxyesters, polyvinyl alcohol (PVA), chitosan, alginic acid, zein, and gelatin.

[0058] In some embodiments, the bark flour comprises coffee granules in a ratio from 1 :0.01 to 1:0.2 (w / w) respectively, coffee granules acting as moisture corrector and processing aid, facilitating and / or improving the production process.

[0059] In some embodiments, the bark flour comprises cacao pulp in a ratio from 1 :0.05 to 1:0.1 (w / w) respectively, as a lubricant which acts as processing aid, facilitates and / or improves the production process.

[0060] In some embodiments, the bark flour comprises a modified surface treated with a compatibilizing agent. As used herein, the term “compatibilizmg agent” refers to a substance added to improve the compatibility between two or more materials that would not normally mix well. In the case of bark flour, a compatibilizing agent is added to enhance its interaction with the biopolymer.

[0061] In some embodiments, the compatibilizing agent comprises water, glycerin, a polyol, a biopolyol, urea, polycarboxylic acid, a, plant-based polycarboxylic acid, or any combination thereof.

[0062] In some embodiments, the compatibilizing agent, comprises citric acid, urea, water, glycerin, or any combination thereof. In some embodiments, the compatibilizmg agent, comprises from 5 to 25 g of citric acid or urea, from 150 to 300 ml of water. In some embodiments, the compatibilizmg agent comprises from 0.1 to 20 g of glycerin.

[0063] The present disclosure is based, in part, on the finding that a compatibilizing agent added to the bark flour, improves its compatibility with the biopolymer, increasing the efficiency of compounding, and accordingly improving the miscibility of filler (bark flour) and matrix (biopolymer). A compatibilizing agent improves the bonding between the bark flour and the biopolymer. Crosslinking provides improved barrier properties of the final product.

[0064] In some embodiments, the biocomposite comprises a coating layer surrounding at least a portion of a surface of the biocomposite, wherein the coating layer comprises a bio-polymer or a natural wax.

[0065] Non-limiting examples of natural wax include vegetable wax, ester of montanic acid with polyols, Chinese wax, and barrier waxes.

[0066] In some embodiments, the coating layer is applied on the inner surface of a packaging.

[0067] In some embodiments, the biocomposite is in the form of a sheet or a pellet. According to the present disclosure, a shape of the bioconiposite is determined by the mixing method. In some embodiments, with twin-screw compounding, either sheets or pellets are produced. In some embodiments, a sheet is used for heat-pressing processing. In some embodiments, a pellet (granule) is used for injection molding processing.

[0068] The biocomposite is biodegradable, as all the components are biodegradable.

[0069] In addition, the biocomposite is a moisture absorbing composite.

[0070] As used herein, the term “moisture absorbing composite” refers to a material that absorbs moisture from its surroundings. Such composites are used in various applications to control moisture levels, non-limiting examples include building materials, electronic devices, packaging, textile, and medical applications. An absorption capacity of a moisture-absorbing composite as described herein can be measured using various techniques known in the art and will become apparent to a person skilled in the art.

[0071] In some embodiments, the effectiveness of the material in regulating humidity levels and managing moisture is accessed by measuring the relative humidity (RH). Reference is made to Example 4 and Example 5 of the present application. Delta RH (ARH) refers to the change in relative humidity (RH) experienced by the material. In the context of moisture absorption, it is used to describe how much the relative humidity increases in the surrounding environment as a result of moisture being absorbed by the material. This measurement provides the effectiveness of the material in regulating humidity levels and managing moisture. A higher ARH indicates that thematerial is absorbing more moisture from the air, making it more suitable for applications for controlling humidity levels.

[0072] In some embodiments, the biocomposite further comprises a natural additive selected from the group consisting of: a coloring agent, a filler, a release agent, a binder, and any combination thereof.

[0073] According to the present disclosure, the use of a biocomposite as described hereinabove is for monitoring and / or controlling humidity in a closed space.

[0074] According to the present disclosure, the use of a biocomposite as described hereinabove is for construction material, in food, cosmetic, medicine, chemical-, or electronic-product packaging, or any combination thereof.

[0075] A product according to the present disclosure comprises the biocomposite.

[0076] In some embodiments, the product is selected from the group comprising: construction material, a bottle, a container, a package, a cap, a piece of disposable medical equipment, or any combination thereof.

[0077] In some embodiments, the product is a package. In some embodiments, the package protects goods from moisture damage during storage and / or transportation.

[0078] Figure 1 shows the product 3 according to the present invention comprising a vessel 1 with solution provided for set up of humidity, a humidity sensor 2 and a polyethylene film 4 covering the package.

[0079] The present disclosure is based, in part, on the finding that biocomposites as described hereinabove as packaging, are sustainable alternatives to known petroleum-based plastics. The present disclosure is based, in part, on the finding that products such as packages present a solution with controlled humidity management capabilities, with application in various subfields within packaging technology.

[0080] In some embodiments, the product is injection-molded.

[0081] In some embodiments, the product further comprises a moisture sensor and / or a temperature sensor.

[0082] According to the present disclosure, a use of a product as described hereinabove, is for monitoring and / or controlling of the humidity in a closed space.

[0083] According to the present disclosure, a use of a product as described hereinabove, is in food, cosmetic, medicine, chemical-, or electronic-product packaging, or any combination thereof.

[0084] A method for producing a biocomposite comprises: bark preparation, flour treatment, compounding, sheet or pellets forming, barrier layer application, thermoforming, or any combination thereof.

[0085] In some embodiments, bark preparation comprises washing, sorting, and grinding bark into flour with pre-defined size.

[0086] In some embodiments, flour treatment comprises modifying bark flour surface with a compatibilizmg agent, thereby providing an increased interaction with a polymer.

[0087] In some embodiments, compounding comprises mixing bark flour with a biopolymer in a single or two-stage process. In some embodiments, mixing is using a twin-screw compounder.

[0088] In some embodiments, sheet forming comprises extruding a composite mixture into sheets.

[0089] In some embodiments, a barrier layer application includes application of a barrier layer, thereby improving moisture control and shelf life.

[0090] In some embodiments, thermoforming comprises shaping the sheets into desired forms using heat and pressure.

[0091] In some embodiments, the method for producing a biocomposite comprises: i) contacting a biopolymer comprising an ammo (-NH?.) or hydroxyl (-OH) side group, with 30 to 85% (w / w) of a bark flour with a particle size from 500 to 1500 mesh, ii) forming a homogeneous biocomposite. In some embodiments, contacting is at a temperature from 100 to 200 °C. In some embodiments, contacting is at a temperature from 120 to 160°C. In some embodiments, contacting comprises mixing the biopolymer and the bark flour under mechanical mixing.

[0092] In some embodiments, the bark flour is gradually added to the biopolymer.

[0093] In some embodiments, the method further comprises a step hi) shaping the biocomposite into pellets or sheets.

[0094] In some embodiments, the method further comprises a step iv) applying a coating layer comprising a bio-polymer or a natural wax to the biocomposite, wherein applying is by coextrusion, pressing, casting, spraying, or any combination thereof.

[0095] In some embodiments, the method further comprises a step preceding step i) of treating the bark flour with a compatibilizmg agent comprising water, glycerin, a polyol, preferably a biopolyol, urea, poly carboxylic acid, or any combination thereof, at a temperature between 70°C and 100°C. In some embodiments, the step is performed in a high-speed mixer. In some embodiments, the step is performed from 1000 to 3000 rpm.

[0096] In some embodiments, the compatibilizing agent comprises from 5 to 25 g of citric acid or urea, from 150 to 300 ml of water. In some embodiments, the compatibilizing agent comprises from 0.1 to 20 g of glycerin.

[0097] According to the present disclosure, a method for producing a product as described hereinabove, includes: a) providing a template comprising a wall defining a cavity, wherein the shape of the product is at least partially predetermined by the shape of the wall; b) contacting the template with a biocomposite as described hereinabove, to at least partially fill the cavity, wherein the contacting is carried out by casting, injection molding, extrusion, compression, thermoforming and / or any combination thereof, thereby obtaining the product.

[0098] In some embodiments, the method further comprises a step of releasing the product from the template, wherein releasing is preferably after waiting a period of time.

[0099] As used herein the term “about” refers to ±10 %.

[0100] The terms "comprises", "comprising", "includes", "including", “having” and their conjugates mean "including but not limited to".

[0101] The term “consisting of’ means “including and limited to”.

[0102] The term "consisting essentially of means that the composition, method or structure may include additional ingredients, steps and / or parts, but only if the additional ingredients, steps and / or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure.

[0103] The word “exemplary” is used herein to mean “serving as an example, instance or illustration”. Any embodiment described as “exemplary’” is not necessarily to be construed as preferred or advantageous over other embodiments and / or to exclude the incorporation of features from other embodiments.

[0104] The word “optionally” is used herein to mean “is provided in some embodiments and not provided in other embodiments”. Any particular embodiment of the disclosure may include a plurality of “optional” features unless such features conflict.

[0105] As used herein, the singular form “a”, “an” and “the” include plural references, unless the context clearly dictates otherwise. For example, the term “a compound” or “at least one compound” may include a plurality of compounds, including mixtures thereof

[0106] Throughout this application, various embodiments of this disclosure may be presented in a range format. It should be understood that the description in range format is merely forconvenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, a description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0107] Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral), within the indicated range. The phrases “ranging / ranges between” a first indicate number and a second indicate number and “ranging / ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.

[0108] As used herein the term “method” refers to manners, means, techniques, and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques, and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, pharmacological, biological, biochemical and medical arts,

[0109] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the disclosure. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.[Oil 0] Various embodiments and aspects of the present disclosure as delineated hereinabove and as claimed in the claims section below find experimental support in the following examples.EXAMPLES

[0111] Reference is now' made to the following examples, which together with the above descriptions illustrate some embodiments of the disclosure in a non-limiting fashion.Materials and methodsBark flour preparation[Oil 2] According to the present disclosure, a process as described herein comprises i) washing and ii) sorting a bark. This includes several stages, to clean the bark from moss, soil, and other unwanted materials. The sorting stage divides the bark into large and small samples and removes wood residues.[Oi l 3] In some embodiments, a first step is i) washing the bark. This step includes placing the bark in special tanks or chambers where mechanical or water-based methods are used to remove various contaminants. In some embodiments, this involves pressure washing or immersing the bark in water. This allows the removal of dust, dirt, microorganisms, and other impurities.

[0114] In some embodiments, the previous step is followed by ii) the sorting step which includes the classification of the bark according to predefined criteria such as size, thickness, and quality. The sorting equipment includes vibrating screens, belt conveyors, or manual methods. This allows the separation of the particular types of bark i.e. separation of a particular type or quality for different applications, as well as for separating residual wood.

[0115] In some embodiments, the process further comprises iii) a bark grinding process, that involves several stages, while in each stage the material is crushed and separated into smaller pieces.

[0116] First stage i.e. crushing into chips (3-5 cm): large pieces of bark are subjected to a crushing process until chips of 3-5 cm are obtained. This can be achieved, for example, by using specialized equipment such as crushers or disk crushers that break down large pieces of bark into more manageable fragments.

[0117] Second stage i.e. milling on a hammer crusher with a 5 mm sieve. In this step, the resulting chips are milled on a hammer crusher with a 5 mm sieve to reduce the size of the material, creating a fine structure. The hammer crusher uses rotating hammers to grind the chips into a finer fraction. The process is performed using a sieve that determines the final particle size.

[0118] Third stage i.e. grinding on a hammer crusher with a 1.5 mm sieve and sieving on a 2 mm sieve. In this stage, the flour obtained after primary milling is subjected to additional crushing on a hammer crusher with a finer 1.5 mm sieve to obtain a finer texture. The resulting material is then sieved on a 2 mm sieve to ensure homogeneity and the desired size of the final product.

[0119] The moisture content of the received flour is measured according to the standard.

[0120] The moisture content should be between 5-16% for adequate processability. If the moisture exceeds this value, the flour must be dried depending on the actual moisture content.

[0121] The drying methods that can be used are described below;

[0122] Air drying is the most common method of drying bark flour. Heated air is used as the dry ing agent and the temperature can reach 100-150 °C. Air drying can be a continuous or batch process.

[0123] Hot Steam Drying is the method of drying that allows for better quality products because steam does not oxidize the bark flour. Hot steam drying is carried out in special steam dryers.

[0124] Infrared drying provides bark flour with a high initial temperature. It is carried out in special infrared dryers.

[0125] Fluidized bed drying allows the bark flour to be dried evenly. It is carried out in special fluidized bed dryers.

[0126] Vacuum drying provides bark flour with lovv moisture content and high dispersibility. It is carried out in special vacuum dryers.Treatment of bark flour with a compatibilizing agent[01271 The process of treating bark flour in a compatibilizing agent is used to modify the surface of the bark flour to improve its interaction with the polymer matrix in the composite and includes the following steps:

[0128] Loading the bark flour into a high-speed mixer while the volume of the feed material is determined by the requirements of the process.

[0129] Heating the bark flour inside the mixer to a temperature of about 90°C using a thermal jacket.

[0130] High-speed mixing 1000-3000 rpm once the set temperature has been reached to ensure intensive mixing of the flour, create an even heat distribution, and prepare the material for chemical action.

[0131] Feeding a solution in the form of a finely dispersed cloud containing urea, citric acid, or other poly-basic carboxylic acid in water or glycerin into the mixer through a special nozzle. This solution is added to the flour to carry out the chemical reaction.

[0132] Addition of the composition of the solution, 5 to 25 g of citric acid or urea to 250 ml of water and mixing until a clear solution is obtained which is followed by addition of 0 to 20 g of glycerin.

[0133] Addition of the obtained solution to the flour, particularly, 5 to 100 grams of solution per 1 kg of flour, depending on the type of bark and the type of polymer matrix.

[0134] Prolonged stirring to achieve uniform distribution of the chemical components throughout the entire mass of flour. This step may take some time to ensure sufficient interaction of all components.

[0135] Temperature, time and other parameters can be monitored during the process to ensure that the treatment is effective, and the desired product quality is achieved.

[0136] Compounding can be done either in a single stage or in a decidedly multistage mixing process.Two-stage process using a twin-screw compounderFirst stage - Pellet Preparation

[0137] Pellets of biopolymers (e.g., starch-based polymer, gelatin, alginate, zein and other plant proteins and polysaccharides with reactive side groups) are loaded into the compounder.

[0138] A system of lateral dispensers introduces the prepared bark flour into the zones where the polymers have already melted. Material cylinder may contain from one to two such zones. The bark flour is gradually mixed with the biopolymer matrix in the field of mechanical action of screws.

[0139] At this stage of production, pellets are formed and cooled using fans on a dry conveyor or in air ducts after the annular cuting process from the die head.Second stage - Sheeting

[0140] Additional mixing: The granules are fed back to the compounder where additional components are added, or further mixing is carried out to improve the homogeneity of the composition.

[0141] Sheet Forming: The material is fed into a twin-screw or single-screw extruder where sheets are formed. The extruder may have a forming nozzle that gives the material the desired profile.

[0142] The sheets are cut and stored in a dry room to maintain the moisture content below 1%.Single stage process using twin screw' compounder

[0143] Material loading: Biopolymer matrix and bark flour are loaded into the compounder by means of a system of lateral metering units at different locations in the cylinder as described previously.

[0144] Mixing and forming: The materials are mixed and subjected to the mechanical action of augers to form a homogeneous composite. As the material moves through the cy linder, it can be further processed to obtain the desired texture and structure.

[0145] At the outlet of the compounder, a head is installed to form the sheets or pellets.

[0146] In both cases, the use of a lateral metering system allows the introduction of filler at different points in the cylinder, which can be important to achieve optimum mixing.

[0147] Screw speed and temperature are controlled to ensure efficient mixing and product formation.

[0148] A cooling system can be used to control the process temperature.

[0149] These processes allow' the creation of bioconiposite sheets filled with prepared bark flour.

[0150] In some embodiments, biocomposite sheets are coated with a coating layer, using various methods, as described hereinafter.Co-extrusion of the coating layer using polymer from the matrixPreparation of the coating material

[0151] The polymer used in the sheet matrix is selected and blended in a twin-screw' compounder with additional ingredients such as colorants.

[0152] The coating layer is applied to the surface of the hot sheet using the co-extrusion method, immediately after it has been formed as described above.

[0153] In some embodiments, the coating layer is pressed onto the sheet with a heated roller or after IR heating of the sheet, to improve the bonding of the coating

[0154] The sheet is subjected to a cooling process to fix the coating layer.Application of coating wax by spraying

[0155] The sheet just formed in the extrusion process is fed into the spraying area.

[0156] The molten coating is sprayed onto the hot surface of the sheet.

[0157] The sheet is cooled to allow the wax to quickly solidify and lock onto the surface.Process of molding the product by thermoforming using a biocomposite sheet

[0158] The biocomposite sheets obtained after the previous processes are prepared for thermoforming.

[0159] The correct sheet thickness is ensured and shapes are cut to fit the final products or the width of the thermoforming machine's convey or belt.

[0160] The biocomposite sheets are placed in a therniopress mold, where they are heated to melting temperature using infrared (IR) heating elements and pressurized to form.

[0161] The thermoforming process can be controlled by vacuum, air pressure and temperature to create the desired product shape.

[0162] Once thermoforming is complete, the mold with the sheet is moved to a press, which applies additional pressure to improve contact between the bark flour biopolymers and the polymer matrix.

[0163] At this time, cross-linking of the matrix with the biopolymers occurs as the mold temperature rises to a value in the range of 150-250°C. This process provides chemical bonding between the components.

[0164] After pressing and cross-linking, the product is left in the mold to cool. Cooling helps to fix the shape and structure of the product.

[0165] In some embodiments, additional cooling steps or the introduction of additional cooling processes are used to control the cooling rate and degree of fixation.

[0166] Once the desired hardness and shape is achieved, the product is removed from the mold.EXAMPLE 1

[0167] Bark of spruce, oak, or maple, manually removed or using a wood debarking machine, was ground on a coarse grinder for mulching purposes. This process aims to produce chips ranging in size from 3 to 6 cm.

[0168] Poplar and Black Locust barks were pre-cleaned from large fibers of the inner bark before grinding in the mulch grinder.

[0169] For walnut bark, no pre-grinding was required.

[0170] After coarse grinding, the obtained chips were sent for further milling in a hammer mill with a 5rnm sieve.

[0171] The coarsely ground flour was further processed in a hammer mill with the sieve size of 1.5-0.5 mm.

[0172] Alternatively, instead of two stages of grinding in a hammer mill, a single mill with particle size control in the range of 500-800 mesh can be used.

[0173] The moisture content of the obtained flour v / as measured using the ASTM D4442 method A. If the moisture content exceeds 12±2 wt % of the flour, it was further dried in a hot air or steam dryer. Other non-oxidizing drying methods are also permissible.

[0174] The compatibilizing agent was prepared using a high-speed mixer-homogenizer. The composition of the compatibilizing solution was as follows: Water 80 wt%, Glycerin 10 wt%, Citric acid 10 wt%. Mixing was carried out at a temperature of 90° C.

[0175] The application of the compatibilizing agent onto the surface of pine bark flour particles was carried out using a high-speed universal mixer. For this purpose, pine bark was heated to a temperature of 90° C at a mixing speed of 300-600 rpm. Subsequently, the mixing speed was increased to 1500-3000 rpm, and the compatibilizing solution was introduced into the mixing vessel through a nozzle under pressure at a rate of 1 nil / min. Compatibilizing solution to bark flour ratio was 1:99. The mixing process was conducted for 15 min,

[0176] The obtained pre-processed flour was mixed with granules or powder of a biopolymer, such as thermoplastic starch (TPS), polyvinyl alcohol (PVA), chitosan, alginic acid, gelatin, zein, or any other biopolymer with reactive -NHj or -OH side groups in the main chain.

[0177] Flour-polymer ratio was 1 : 1, or 3.5:1 ,

[0178] The prepared mixture was loaded into the metering unit of a twin-screw compounder, with an L / D value of at least 24. Table 1 presents the temperature by zone of compounder.Table 1. Temperature by zone of compounder

[0179] The strands were cooled by air, either by fans on the conveyor or by centrifuges during hot head cutting. Instead of a pellet, 2mm thick sheets can be produced.

[0180] In some embodiments, flour is introduced without premixing with the biopolymer through the side feeder of the compounder immediately after the melting zone.EXAMPLE 2

[0181] After granulation, the residual moisture content of the granules was determined. It should not exceed 5%. After that the polymer melt flow index (MFI) was analyzed according to ASTM DI 238 method. The results are presented in Table 2.Table 2.EXAMPLE 3

[0182] The resulting pellets were poured into a single-screw worm-type injection molding machine with a temperature in the material barrel and at the head of 130°C. The temperature in the mold was 100°C during pouring, and increased to 200°C for 10 seconds immediately after injection.EXAMPLE 4HUMIDITY ADSORPHON

[0183] The packaging made of the described material was able to control humidity in a confined space. This statement is confirmed by the results of the experiment conducted in accordance with the following methodology:

[0184] For the experiment desiccators were used, inside of which a solution of table salt was placed to control relative humidity. The supersaturated NaCl salt solution provided a relative humidity of 74.87+0.12 at 35 °C. The exciters were placed in a thermal cabinet. When the target humidity’ and constant temperature were reached, parts of material or chips of the package were placed inside the desiccators. Relative humidity’ inside the desiccators was measured using a DHT22 digital humidity’ sensor or similar device for 12 hours. Data obtained in the desiccator without material were used as a control (RHc). The results obtained after stabilization of the relative humidity inside the desiccator were averaged (RHs) and confidence intervals determined, and the mean value with the sample was subtracted from the mean value of the control measurement.

[0185] ARH = RHs - RHc

[0186] This experiment was repeated using other solutions that provide different values of relative humidity: sodium hydroxide, sodium iodide, and magnesium chloride.

[0187] The results obtained are presented in Table 3.Table 3.

[0188] It can be seen that packaging samples with different bark types exhibit different results, opening up the possibility' of producing a material specifically' customized to meet specific moisture requirements.EXAMPLE 5MAINTAINED HUMIDITY

[0189] The moisture level maintained inside the package was determined using a similar method. However, a moisture sensor was placed inside the manufactured product and then the product was hermetically sealed. After stabilization, the data obtained were averaged and the values for the described samples are presented in Table -4.Table 4.EXAMPLE 6BIODEGRADABILITY

[0190] Biodegradation was investigated under controlled conditions using the Sturm method. This method involves continuous monitoring of carbon dioxide concentration in the reactor.

[0191] For the experiment, sodium hydroxide solution and biodegradation media such as crunt, compost, and other components were introduced into two vessels. Shredded packaging materials were added to one of the vessels and polyethylene of the same mass was added to the other vessel.The difference in pressure between the vessels is measured using an MPX4250DP differential pressure sensor or similar device. The biodegradation of the material releases carbon dioxide, which interacts with sodium hydroxide, resulting in a pressure drop. The greater the pressure reduction, the more material has biodegraded. By differentiating the resulting graph by time, the biodegradation rate of the material is determined.

[0192] The biodegradation rates of the indicated materials are presented in Table 5.Table 5.EXAMPLE 7 STRENGTH

[0193] Material strength wras determined by ASTM D638M, ASTM D790 and ASTM D256 (Table 6).Table 6.EXAMPLE 9

[0194] In some embodiments, the sheets obtained in Example 6 are coated with a coating layer. The coating layer improves the quality of the packing by providing antioxidant and antimicrobial properties, oxygen scavenging, CO2 release, humidity maintaining and / or controlling depending on the agent incorporated into the matrix. The coating layer is applied only in the inner side of the packaging, which will be in contact with the food.[01951 The coating may be performed by two methods described below.

[0196] Preferably, the coating method includes a co-extrusion, i.e. applying a layer of biopolymer which is a matrix in biocomposite material as described in Example 1, and crosslinking agent such as citric acid, urea or formaldehyde.

[0197] Another coating method includes applying melted wax, such as Solenis TopScreen TM or any other coating wax made from palm wax or other vegetable wax, to the resulting sheet using a ramp with nozzles.

[0198] After molding in the injection molding machine, the coating wax melt can be applied to the final product with a robotic nozzle, directly on the inside, before removal from the mold or on the conveyor before packaging.

[0199] Although the disclosure has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

Claims

CLAIMS1. A biocomposite comprising: a polymeric matrix comprising at least one biopolymer comprising an ammo ■ ••M l’) or hydroxyl (-OH) side group, and from 30 to 85% (w / w) of a bark flour with a particle size from 500 to 1500 mesh.

2. The biocomposite according to claim 1, wherein said biopolymer and said bark flour are cross-linked.

3. The biocomposite according to any one of claims 1 to 2, wherein said biopolymer comprises a protein-based biopolymer, a polysaccharide, peptidoglycan, polyhydroxyalkanoates (PHAs), or any combination thereof.

4. The bioconiposite according to any one of claims 1 to 3, wherein said bark flour comprises tree bark, preferably bark of oak, poplar, elm, pine, black locust, acacia, eucalyptus, beech, hornbeam, chestnut or any combination thereof.

5. The biocomposite according to claim any one of claims 1 to 4, wherein said bark flour comprises coffee granules in a ratio from 1:0.01 to 1:0.2 (w / w) respectively.

6. The biocomposite according to claim any one of claims 1 to 5, wherein said bark flour comprises cacao pulp in a ratio from 1 : 0.05 to 1 :

0. 1 (w / w) respectively.

7. The biocomposite according to claim any one of claims 1 to 6, wherein said bark flour comprises a modified surface treated with a compatibi Sizing agent comprising water, glycerin, a polyol, preferably a bio-polyol, urea, polycarboxylic acid, preferably plant-based polycarboxylic acid, or any combination thereof.

8. The biocomposite according to any one of claims 1 to 7, wherein said biocomposite comprises a coating layer surrounding at least a portion of a surface of said biocomposite, wherein said coating layer comprises a bio-polymer or a natural wax.

9. The biocomposite according to claim any one of claims 1 to 8, wherein said biocomposite is in the form of a sheet or a pellet.

10. The biocomposite according to claim any one of claims 1 to 11 , further comprising a natural additive selected from the group consisting of: a coloring agent, a filler, a release agent, a binder, and any combination thereof.

11. A product comprising the biocomposite according to claim any one of claims 1 to 10, wherein said product is a bottle, a container, a package, a cap, a disposable medical equipment, a construction material, or any combination thereof.

12. A method for producing a biocomposite according to any one of claims 1 to 10, comprising: i) contacting a biopolymer comprising an amino (-NH2) or hydroxyl (-OH) side group, with 30 to 85% (w / w) of a bark flour having particle size from 500 to 1500 mesh, preferably at a temperature from 100 to 200 °C, more preferably at a temperature from 120 to 160°C; ii) homogenizing biocomposite.

13. The method according to claim 12, wherein contacting comprises mixing said biopolymer and said bark flour under mechanical mixing.

14. The method according to claims 12 or 13, wherein said bark flour is gradually added to said biopolymer.

15. The method according to any one of claims 12 to 14, further comprising a step iii) shaping said biocomposite into pellets or sheets.

16. The method according to any one of claims 12 to 15, further comprising a step i v) applying a coating layer comprising a bio-polymer or a natural wax to said biocomposite, wherein applying is by co-extrusion, pressing, casting, spraying, or any combination thereof.

17. The method according to any one of claims 12 to 16, further comprising a step preceding step i) of treating said bark flour with a compatibilizing agent comprising water, glycerin, a polyol, preferably a bio-polyol, urea, polycarboxylic acid, preferably plant-based polycarboxylic acid, or any combination thereof, at a temperature between 70°C and 100°C, preferably said step is performed in a high-speed mixer, more preferably from 1000 to 3000 rpm.

18. The method according to claim 17, wherein said compatibilizing agent comprises citric acid, urea, water, glycerin, or any combination thereof, preferably from 5 to 25 g of citric acid or urea, from 150 to 300 ml of water, and optionally from 0.1 to 20 g of glycerin.

19. A method for producing the product according to claim 11, the method comprising: a) providing a template comprising a wall defining a cavity, wherein the shape of the product is at least partially predetermined by the shape of said wall; b) contacting the template with the biocomposite according to any one of claims 1 to 12, so as to at least partially fill said cavity, w-herein said contacting is carried out by casting, injection molding, extrusion, compression, thermoforming and / or any combination thereof, thereby obtaining the product.

20. The method according to claim 19, further comprising a step of releasing the product from said template.

21. The method according to any one of claims 19 or 20, further comprising a step of introducing a moisture and / or a temperature sensor to the product.

22. Use of the biocomposite according to any one of claims 1 to 10, for controlling humidity in a closed space.

23. Use of the biocomposite according to any one of claims 1 to 10, in construction materials, electronic devices, food, cosmetic, medicine, chemical-, or electronic-product packaging, or any combination thereof.

24. Use of the product according to claim 11 , for controlling humidity in a closed space.

25. Use of the product according to claim 11, in construction materials, electronic devices, food, cosmetic, medicine, chemical-, or electronic-product packaging, or any combination thereof.

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